The invention relates to a coupling for conductor rails, which coupling comprises a middle unit having two pivoting parts pivotable relative to each other about a geometric pivot axis, the pivoting parts being cup-shaped, facing each other with their open sides, and being assembled by rims abutting each other or overlapping each other, one respective holding means for a cantilevering multipole conductor rail for attachment of lighting fixtures being arranged on each one of these pivoting parts so as to project from the outer side of the pivoting parts in a radial direction with respect to the pivot axis, said holding means being provided with electrical connecting conductors for a connection with conductor rails to be attached there, and wherein the individual connecting conductors of the one holding means are each electrically conductively connected with a connecting conductor of the other holding means.
Couplings of the afore-mentioned type mainly serve to assemble conductor rails which in turn are provided for attaching and supplying an electric current to lighting fixtures, in a manner that a conductor rail will be available at those sites where, following a given plan, lighting fixtures are to be arranged, so as to provide them with electric current. Couplings of the afore-mentioned type are known from DE 21 31 065 B. With the latter it is possible to interconnect conductor rails at selectable angular positions relative to each other. In these known couplings, a respective connecting conductor of one holding means is conductively connected with a connecting conductor of the other holding means via a flexible cable which is guided through the middle unit. This embodiment is comparatively complicated as regards the production of the individual parts of the coupling and also as regards its assembly, and mention may be made of the necessity of connecting the flexible cables with the connecting conductors and the required manipulations when inserting the connecting conductor pairs which are interconnected via these cables, in the holding means. Moreover, also the accommodation of the flexible cables in the middle unit often is difficult because these cables, particularly when they are to conduct higher amperages, must be comparatively thick, the required insulation of these cables further increasing the thickness of the latter, and since, considering the required pivotability of the holding means relative to each other, the length of these flexible cables to be housed in the middle unit must be rather large; the latter may also impede the movability of the holding means relative to each other.
It is an object of the present invention to provide a configuration of a coupling of the initially defined kind in which the afore-mentioned disadvantages are avoided.
The inventive coupling of the initially defined kind is characterized in that the connecting conductors are formed as electrically conductive rods extending from the holding means into the interior of the pivoting parts of the middle unit, wherein, in the vicinity of the pivot axis, a respective connecting conductor of one holding means slidingly contacts a connecting conductor of the other holding means. By this configuration, the object set out above can well be met in a simple manner. A structurally simple coupling is obtained the parts of which can be produced with little expenditures and can be assembled with a simple manipulation and which is also easily adjustable when in use, a good electrical connection of the connecting conductors one to another being provided. Particularly with a view to mounting the individual construction parts, a suitable embodiment results if it is provided that a connecting conductor leads directly from each holding means, in the half attached on one of the pivoting parts, into the interior of this pivoting part, and a connecting conductor from the other half of the respective holding means leads into the interior of the respective other pivoting part, passing the gap between this half and the respective other pivoting part of the middle unit through a peripherally extending slot in the wall of the respective other pivoting part. In this respect, it is possible to provide for a very good electrical contact between the electrical pathways leading from the one holding means to the other holding means in a structurally simple manner and over long periods of time with an embodiment which is characterized in that the ends of the connecting conductors located in the interior of the pivoting parts of the middle unit each carry a ring which surrounds the pivot axis, a respective ring of a connecting conductor of the one holding means slidingly contacting a ring of a connecting conductor of the other holding means. This embodiment also ensures a good positioning of the connecting conductors over extended periods of time. This embodiment may also advantageously be supplemented in that an annular insulating spacer which likewise surrounds the pivot axis is arranged between pairs of slidingly abutting rings.
For providing the contact between the connecting conductors in the holding means of the coupling and the conductor rails to be applied to these holding means it is suitable if it is provided that the connecting conductors are mounted in the holding means so as to be transversely displaceable and designed to be resilient in transverse direction. A transversely displaceable and resilient mounting of the connecting conductors may also advantageously be obtained with an embodiment which is characterized in that the connecting conductors are mounted in the holding means so as to be transversely displaceable therein and in that springs are provided which act in transverse direction of the connecting conductors and engage on the connecting conductors.
For the production and assembly of the individual parts which, in the coupling designed according to the invention, are particularly important with respect to the structure, i.e. the two parts of the middle unit which are pivotable relative to each other, and the holding means, it is particularly advantageous if it is provided that each one of the holding means is formed by an attachment part directly located on one of the two pivoting parts of the middle unit and an externally following plug-in connection part to which a conductor rail can be attached by positive connection. Furthermore, this embodiment also has the advantage that for an adaptation to various forms of conductor rails it is merely necessary to design the plug-in connection parts in conformity with the rails, whereas the middle unit with the attachment parts does not require an adaptation to the shape of the conductor rail; moreover, by providing attachment parts directly located on the mutually pivotable parts of the middle unit, as well as plug-in connection parts following these attachment parts in outward direction, mounting of the holding means with their electrical connecting ledges on the mutually pivotable parts of the middle unit is substantially facilitated. Advantageously, the attachment part may be integrally formed in one piece with its associated pivoting part.